• 한국터널지하공간학회 논문집
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• 제18권1호
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• pp.61-74
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• 2016

본 논문에서는 화강풍화대를 통과하는 슬러리 TBM 굴진 중 지표 침하 및 체적손실 산정에 관한 사례 연구를 수행하였다. 터널 천단 침하 계측 결과로부터 TBM 굴진 단계별 침하 발생 경향을 분석하였고, 횡방향 지표 침하 트라프로부터 굴진 중 체적손실 및 트라프 변수를 산정하였다. 또한, 체적손실 산정 모델을 이용하여 지반 특성과 굴진 중 측정된 기계데이터가 반영된 굴진 단계별 체적손실을 산정하였으며, 이를 실제 계측 결과와 비교 분석하였다. 슬러리 TBM의 경우 대부분의 지표침하는 쉴드 본체 통과 및 뒤채움 주입 이후 발생하는 것으로 나타났고 문헌에 보고된 총 체적손실 및 트라프 곡선 형태가 확인되었다. 실제 굴진 중 체적손실은 굴진 단계별로 쉴드손실 예측값의 90%, 테일부 손실 예측값의 60% 수준으로 분석되었고, 쉴드 손실에 비해 테일부 손실의 편차가 큰 것으로 나타났다.

• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.43-51
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• 1995

For the stress-strengh function, hierarchical Bayes estimations considered under squared error loss and entropy loss. In particular, the desired marginal postrior densities ate obtained via Gibbs sampler, an iterative Monte Carlo method, and Normal approximation (by Delta method). A simulation is presented.

• Journal of the Korean Data and Information Science Society
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• 제6권1호
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• pp.39-51
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• 1995

This paper deals with the problem of obtaining some Bayes estimators of Rayleigh reliability function in a time censored sampling with incomplete information. Using the priors about a reliability function some Bayes estimators are proposed and studied under squared error loss and Harris loss.

• 경영과학
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• 제28권3호
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• pp.73-82
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• 2011

Basel II advanced measurement approaches for operational risk need to estimate the frequency and severity distribution of operational losses. Due to lack of internal loss data, the estimation is impossible in many cases and so external loss data might be used by scaling on asset or gross income. To get around lack of loss data, scenario analysis combined with loss distribution approach can be useful in calculating the capital charge of operational risk. However, scenario based loss distribution approach requires much time and effort. Instead we may apply the analytic hierarchy process to measure operational risk of financial institutions. The analytic hierarchy process combined with loss distribution approach is to estimate the capital charge of operational risk in other areas based on the operational VaR in an area with sufficient loss data. AHP provides a tool for timely measurement of operational risk in this rapidly changing global environment.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1345-1351
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• 2013

Variable iron loss as function of current phase angle of Interior Permanent Magnet Synchronous Motor(IPMSM) was calculated through Curve Fitting Method(CFM). Also, a magnetic flux density distribution of iron core according to current phase angle was analyzed, and an iron loss calculation was performed including harmonic distortion. The experiment was performed by production of non-magnetizing model for the separation of mechanical loss, and the iron loss was calculated by the measurement of input using power analyzer and output power using dynamometer. Some error was generated between experimental results and calculation value, but an iron loss diminution according to current phase angle followed a same pattern. So, errors were generated by measurement, vibration, noise, harmonic distortion loss, etc.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.723-724
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• 2008

The rotational loss is one of the most important problems for the practical applications of PM synchronous motor/generator. This rotational loss is divided as the mechanical loss by windage and bearing and iron loss by hysteresis loop and eddy current in the part of the magnetic field. So, In this paper, a double-sided PMSM/G without the iron loss is designed by analytical method of the magnetic field and estimation of the back-EMF constant represented as the design parameter. This design model consists of the double-sided PM rotor with Halbach magnetized array and coreless 3-phase winding stator. The results show that the double-sided PMSM/G without iron loss can be applicable to the required system without the rotational loss.

• 대한전자공학회논문지TC
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• 제41권8호
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• pp.63-68
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• 2004

채널 추정 오차가 존재하는 상황에서 MIMO 시스템의 채널 용량을 수식적으로 분석한다. 수식적인 분석에 의해, 채널 용량은 평균 신호 대 잡음비 (SNR) 와 함께 채널 추정 오차 (MSE)에 영향을 받음을 알 수 있다. 또한 본 논문에서는 평균 SNR 과 채널 용량의 손실량이 제한되어 있을 경우, 허용가능한 채널 추정 오차를 구함으로써 주어진 시스템에 적합한 채널 추정기법을 선택하는 기준을 제시한다. 실험 결과로부터 1 bps/Hz 채널용량의 손실에 대해 허용 가능한 채널 추정 오차는 20dB와 40dB의 평균 신호 대 잡음비에서 각각 10/sup -2/와 10/sup -4/임을 확인 할 수 있다.

• 로봇학회논문지
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• 제14권4호
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• pp.357-362
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• 2019

This paper proposes a model and train method that can real-time detect objects and distances estimation based on a monocular camera by applying deep learning. It used YOLOv2 model which is applied to autonomous or robot due to the fast image processing speed. We have changed and learned the loss function so that the YOLOv2 model can detect objects and distances at the same time. The YOLOv2 loss function added a term for learning bounding box values x, y, w, h, and distance values z as 클래스ification losses. In addition, the learning was carried out by multiplying the distance term with parameters for the balance of learning. we trained the model location, recognition by camera and distance data measured by lidar so that we enable the model to estimate distance and objects from a monocular camera, even when the vehicle is going up or down hill. To evaluate the performance of object detection and distance estimation, MAP (Mean Average Precision) and Adjust R square were used and performance was compared with previous research papers. In addition, we compared the original YOLOv2 model FPS (Frame Per Second) for speed measurement with FPS of our model.

• 한국포장학회지
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• 제28권3호
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• pp.237-244
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• 2022

Onions are a significant crop in Korea, and cultivation is increasing every year along with high demand. Onions are planted in the fall and mainly harvested in June, the rainy season, therefore, physiological changes in onion bulbs during long-term storage might have happened. Onions are stored in cold room and at adequate relative humidity to avoid quality loss. In this study, bio-yield stress and weight loss were measured as the quality parameters of net packaged onions during 10 weeks of storage, and the storage environmental conditions are monitored using sensor networks systems. Quality estimation of net packaged onion during storage was performed using the storage environmental condition data through machine learning approaches. Among the suggested estimation models, support vector regression method showed the best accuracy for the quality estimation of net packaged onions.

• 터널과지하공간
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• 제25권5호
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• pp.397-407
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• 2015

본 논문에서는 쉴드 TBM 굴진 중 체적손실 산정과 관련한 기존 사례 및 정량적인 산정 방안에 대한 문헌 분석을 수행하여 장비 형상과 운전 중 주요 기계데이터를 활용한 산정 방안을 도출하였다. 도출된 방안은 기존 문헌에 보고된 토압식 및 이수식 TBM 굴진 사례 분석에 적용되었다. 전반적으로 계측 결과와 잘 부합하는 것으로 나타났으며 일부 차이에 대한 분석을 실시하였다.